There is currently considerable interest in antibodies directed against phospholipids. Several clinical associations with these antibodies have been defined, the strongest ones being with thrombosis and recurrent foetal loss. These antibodies were originally studied in patients with systemic lupus erythematosus, but they have also been found to occur in patients who do not have this disease. This paper describes two such patients and discusses current views on antiphospholipid antibodies.peer-reviewe